Blast gun



Feb. 1, 1938.`

C. B. FLETCHER BLAST GUN Filed April 17, 1.937

2 Sheets-Sheet l Attorneys Patented Feb. 1, 19138 narran sraras BLAST GUN Clarence B. Pletcher, St. Joseph, Mich.

Application April i7, i937, Serial No. 137,576

5 Claims.

This invention relates to sand blasting guns of the type using a high pressure of water for forcing a mixture of the water, sand and air from the nozzle of the gun on to the work or surface to be cleaned or sand blasted.

An object of the present invention is to provide a blasting gunof the character above mentioned characterized by improved means for insuring a thorough mixing of the water, sand and air.

To this end the gun is provided with achember into which sand and air is drawn by suction and into which water under pressure is introduced in a manner to set up a turbulence within the chamber conductive to a thorough mixing of the water with the sand and air to the end that there will be no choking of the orices and as would otherwise occur due to a lack of a proper mixing of the water and. sand.

'A further object of the invention is to provide for such a mixing o1( the water and sand that cleaning of the gun will be necessary occasionally and only after long periods of use.

The invention together with its objects and advantages will be best understood from a study 'of the following description taken in connection with the accompanying drawings whereinn-v Figure l is a sectional View through a blast gun involving the features of the present invention.

Figure 2 is an elevationalview of a jet nozzle.

Figure 3 is an enlarged fragmentary side elevational view. of the gun at the handle end thereof.

Figure 4 is an end elevational View oi the gun viewing the same from the handle end thereof and Figure 5 is a perspective view of a yoke member.

Referring to the drawings by reference numerals it will be seen that in the preferred einbodiment thereof the gun comprises a barrel@ having integral 'therewith a handle t.

Barrel d is bored* to provide av suction and mixing chamber l and a valve chamber 8. Chambers l and 8 are provided with a common or partition Wall a that has a bore therethrough which bore has a conical end i!! forming a valve seat and a threaded end il into which latter end is threaded a jet nozzle i2.

The handle 5 is provided with a bore i3 that opens into the valve chamber B and at the free end thereof the handle 5 is provided with internal threads as at Ii for the coupling thereto of one, end of a hose leading from. a source of water pressure.

` nessun Fitted within the end of the barrel 5 equipped with the chamber t is a packing assembly i4 held in place between an internal shoulder i5 and a hollow gland nut i5.

Having a Working fit through the packing as- 5 sembly it is a valve member il provided at one end with a truste-conical head it normally engaging the seat it. Housed within the hollow of the gland nut it is a coil spring i9 which at one end bears against a shoulder on the valve 10 member il in a manner to yieldably retain the valve head it engaged with its seat it.

For retracting or unseating the valve il there is provided a handle 2l which is forked at one end and at said end straddles the gun handle t and is pivoted to the handle t at opposite sides of the latter as at 22.

The legs of the handle d are substantially L- shaped as shown in Figure `3 and at their free ends are pivotecl as at 23 to the legs of a yoke it that at its closed end is provided with an opening 25 which loosely accommodates the stem of the valve i'i.

On the outer end thereof the stem of valve ii is threaded tol receive a pair of stop nuts 26 with which the closed end of the yoke 2d cooperates for retracting or unseating the valve; ln this connection it will be noted that at the closed end ythereof yoke 2li is provided with lugs or projections 2l that have bearing engagement with the nuts 26 ina manner shown in Figure 3 when the valve operating handle 2i is swung from the position shown in Figure l to the position shown in Figure 3 for unseating the valve Il. Obviously upon release of pressureon handle 2l spring i9 will operate to seat the valve il. Thus it will be seen that the valve il may be controlled by the same hand holding the gunfso that thel other hand of the operator is left free.

The barrel 5 has formed integrally therewith `and in the region of the chamber l, a nipple 28 that is suitably corrugated and. is adapted to have sleeved thereon one end of a hose or ilexible conduit leading from a source of sand supply which is `ieci by air pressure to the chamber l of the gunthrough s aidhose and the bore 29 of the nipple 28.

For the gun there is also provided a nozzle indicated generally by the reference numeral 30. Discharge nozzle 30 comprises a pair of complemental sections 3l, 32. Section 3l is provided at one end with a threaded pin 33 that threads into they chamber equipped end 1 of the gun barrel. At its other end nozzle section 3| is provided with internal threads to receive a threaded(- 55 pin 34 i'ormed' integral with one end of complemental nozzle section 32.y

The bore of the nozzle 30 is materially larger than the bore 35 of jet nozzle I2 herein before referred to, and the bore of the nozzle 30 is lined by a tubing 36 of rubber or other suitable material formed intermediate its end with an integral shoulder 31 that is clamped between an internal shoulder 38 provided integral with the nozzle section 3l and the pin 34 of the nozzle section 32. At the intake end thereof the bore of the lining tube 36 is ilared as at 39.

Nozzle l2 is relatively small and is provided at one end with a threaded portion that threads into the end Il of the bore in the partition wall vsaid bore-with a seat against which said valve 9. The body of the nozzle l2 is providedl with the aforementioned axial bore 35 which at the -end thereofl opening into chamber 8 is iiared as shown.

Intermediate its ends the body of the nozzle I2 is provided with a` diagonal port 40. Thus it will be seen that when valve vi8 is unseated Water from the source of supply passes through the passage i3 in handle 6 into the. chamber 3 and from chamber 8 through the bore 35 of nozzle I2 into the chamberA 1, certain of the water discharging in a stream into the chamber 1 through the port 40 in nozzle |12 in a manner to set up a turbulence andthoroughly agitate the mixture oi.'V theV sand and air entering the chamber 1 to the end that lthe water entering the chamber 1 will be thoroughly mixed with said sand and air, the mixture of sand and water discharging,v under pressure chamber 1-will as above mentioned,not onlyin-. Y sure a thorough mixing of the sandand water through the nozzle 30 of the gun on to the surface to be cleaned.

This setting up voi' Aa. turbulence within the but will also preclude accumulations of wet sand normallyengages, a jet nozzle threaded into said bore of the partition and extending from said partition into said vacuum and mixing chamber, said jet nozzle being provided with an axial bore through which water under pressure passes into said mixing and vacuum chamber, and also bejing provided with a diagonal passage through which a Jet of water passes into the last mentioned chamber to set up a turbulence therein i for insuring a mixing of water and sand fed to the last mentioned chamber, said barrel being provided in the region oi' said last mentioned chamber with a nipple for the attachment of a hose theretol for supplying sand under air pressure to the last mentioned chamber, a nomle mounted on the mixing and vacuum chamber equipped end of said barrel, said anule having a bore therethrough anda tubular member of rubber lining the bore oi? said nozzle.

3. In a sand blast device, a barrel having aligned valve and mixing chambers, respectively,

Vand also having a lateral water inlet for said about the nozzle I2, within the chamber 1, and within the bore 'of the nozzle 30 and as would tend to obstruct and free flow of water and sand from the gun. l y

It is thought that a clear understanding of-.the construction, utility and advantages of an inven tion of this character will be had without a more l detailed description.

Having thus described the invention, what is claimed as new iszv 1'. In a sand blast gun, a barrel provided with a' partition a valve chamber on one side of the partition and a vacuum and mixing chamber at a relatively opposite side o! the partition, an integral handle for said barrel having a water passage therethrough for supplying water to said valve chamber, a spring biased l'reciprocating valve mounted in said barrel, and said partition having .a bore therethrough and provided at one end of said bore with a seat against which said valve normally engages. a iet nozzle threaded into said bore of the partition and extending from said partition into said vacuum and mimng chamber. said jet nozzle being provided with an axial bore through which waterunder pressure passes into said mixing and vacuum chamber, and also being provided with a diagonal passage through which a jet of water'passes into the'last mentioned chamber to set up a turbulence therein for insuring a mixing of water and sand fed to the last mentioned' chamber, said barrel being provided inthe region of said lastf mentioned chamber with a nipple for the attachment of a hose theretoi'or supplying' sand under air pressure to the last mentioned chamber. and anozzle mounted on.

vvalve chamber and a lateral sand inlet for said mixing chamber, together with a partition wall common to said chambers and having a passage therethrough 'and a valveseat at the end of the passage opening into the valve chamber, a valve in the valve chamber normally engaging said seat, means supprting the valve in said chamber for axial shifting movement including a spring yieldably urging said valve into engagement with said seat, saidvalve also having a stem projecting beyond one end of said barrel, a handle member pivotally mounted on said water inlet, a yoke having'legs pivoted to said handle, said yoke at the closed end thereof being provided with an opening loosely accommodating said valve stem, and stop means on said valve stem with which j the closed end oi the yoke engages for unseating said valve incidental to a pivotal movement o! said handle.

4..In a sand blast device, a barrel having aligned valve and mixing chambers, respectively.

and also having a lateral water inlet i'or said valve chamber and a lateral sand-inlet for said mixing chamber, together with a partition wall common to said' chambers and having a passage therethrough and a valve seat at the end of the passage opening into the valve chamber, a valve in the valve chamber normally engaging said seat, means supporting the valve in said chamber for axial shifting movement including a spring yieldably urging said valve into engagement with said seat, said valve also having a stem projecting beyond one end of said barrel, a handle memberfpivotally mounted on said water inlet. a yoke having legs pivoted to-said handle, said yoke at m the closed end thereof being provided with an opening loosely accommodating said valve stem. stop means on said valve stem with which thev closed end o! the yokeengages for unseating said valve incidental to a pivotal movement of said 15 aromas handle, and a jet nozzle threaded into said partition at the side thereof facing the mixing chamber. said jet nozzle having an axial bore aligning with the bore in said partition, and also havling a diagonal bore for directing a stream of water into the mixing chamber in a manner to set up a turbulence therein tending to secure a thorough mixing of the water and sand within said chamber.

5. In a sand blast device, a barrel having aligned valve and mixing chambers, respectively, and also having a lateral water inlet for said valve chamber and a lateral sand inlet for said mixing chamber, together with a partition wall common to said chambers and having a passage therethrough and a valve seat at the end o! the passage opening into the valve chamber, a valve in the valve chamber normally engaging said seat, means supporting the valve in said chamber for axial shitting movement including a spring yieldabiy urging said valve into engagement with said seat, said valve also having a stem projecting beyond one end of said barrel, a handle member pivotally mounted on said waterinlet, a yoke having legs pivoted to said handle, said yoke at the closed endl thereof being provided with an opening loosely accommodating said valve stem, stop means cn said valve stem with which the closed end of the yoke engages for unseatin'g said valve incidental to a pivotal movement of said handle, a jet nozzle threaded into said vpartition at the side thereof facing the mixing chamber, said jet nozzle having an axial bore aligning with the bore in said partition, and also having a diagonal bore for directing a stream of IWater into the mixing chamber in a manner to set up a turbulencel therein tending to secure a thorough mixing oi' the watercand sand within said chamber, and a nozzlethreaded on said barrel and having a bore communicating with said mixing chamber, Vthe bore of said nozzle being of mate` rially greater diameter than the axial bore of the jet nozzle.

. CLARENCE B. FLETCHER. 

